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Volume 44, Issue 10
Displaying 1-10 of 10 articles from this issue
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Naoyuki SEO, Naohito SHIGA, Junichi IWABUCHI, Michio SHIRAI1987 Volume 44 Issue 10 Pages 717-728
Published: October 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSUltraviolet-curing adhesive is widely used for effective adhesion of optical components. However, the optical stress formed in the adhesion process has an important role in the optical performance of the product. This optical stress was studied in a series of adhesion experiments using epoxy adhesives, ultraviolet-curing adhesives, and modified adhesives, by means of a Fizeau interferometer and a polarizing light microscope. The optical stress formation was governed by adhesive properties, curing conditions, the structure and dimensions of the assembly, and an external thermal effect after curing.View full abstractDownload PDF (3555K) -
Hideo TOMIOKA, Sigeru TAKEUCHI, Hideshi KURIMOTO, Yasuyuki TAKIMOTO, M ...1987 Volume 44 Issue 10 Pages 729-735
Published: October 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPhotolysis of S-phenyl thiobenzoates (1) in benzene afforded benzaldehyde, diphenyl disulfide, and biphenyl as major products. This indicates that 1 underwent CO-S bond fission upon photoexcitation. Among the various aryl-substituted S-phenyl thiobenzoates, 4-benzoyl and 4-acetylbenzoate derivatives were photolyzed most efficiently, probably because of involvement of the triplet excited state in the photocleavage of 1. When 1 was irradiated in phenyldiethyleneglycol acrylate, polymer was formed. The efficiency of the photopolymerization was greatly enhanced by the introduction of 4-benzoyl group on the benzoate phenyl ring. It also increased with decreasing its initial concentration. These results suggest that 1 may act as an iniferter and the benzoyl radical initiates polymerization, while the accompanied thiol radical may act as a transfer agent and/or terminator.View full abstractDownload PDF (1008K) -
Seiji SAITA, Tadatomi NISHIKUBO1987 Volume 44 Issue 10 Pages 737-743
Published: October 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSNew photosensitive polymers containing pendant chalcone moieties as photosensitive groups were synthesized by addition reaction of pendant epoxide group in poly (glycidyl methacrylate) (PGMA) with esters having chalcone moieties using tetraethylammonium bromide as a catalyst in diglyme at 100°C. Atlhough the resulting polymer was not soluble when tert-amines were used as a catalyst, soluble photosensitive polymers containing pendant chalcone moieties were prepared with high conversion up to about 80mol% when some quaternary ammonium salts having Cl-, Br-, or I- as a counter anion were used as a catalyst. The polymer obtained by this method showed high photochemical reactivity and practical photosensitivity, and those having a absorption maximum in a longer wave length region or a high molecular absorption showed high photochemical reactivty.View full abstractDownload PDF (1109K) -
Masahiro TSUNOOKA, Shinjiro UENISHI, Makoto TANAKA1987 Volume 44 Issue 10 Pages 745-751
Published: October 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSIt is possible to introduce pendant phenol groups on polymer chains by photo-Fries rearrangement of the pendant phenyl ester groups. These phenol groups are expected to be available as functional groups for dyeing polymer films. Copolymers of phenyl methacrylate (PMA) or S-phenyl thiomethacrylate (SPMA) with methyl methacrylate (MMA) (or styrene (St)) were prepared and their photoreactions were investigated. Upon UV irradiation of PMA copolymers, 2- (or 4-) acylphenol groups were introduced aspendant groups, but in the case of SPMA copolymers the photo-oxida-tion of polymer surface proceeded preferentially. The degree of adsorption of a cationic dye on the irradiated SPMA-MMA films was greater than that of the irradiated PMA-MMA films. The functional groups which were produced by the photo-oxidation of SPMA units were deduced to play an important role in the dyeing.View full abstractDownload PDF (1186K) -
Tetsuji JITSUMATSU, Hideki MATSUBARA1987 Volume 44 Issue 10 Pages 753-760
Published: October 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSUV-and EB-curing properties of various polyol polyacrylates were investigated by the measurements of surface-hardening and conversion of acryloyloxy groups and by ESR spectra. Surface-curability was different for each polyol polyacrylates when the UV-curing process was carried out in air. This behavior was caused by the inhibition effect of oxygen at the surface of polyol polyacrylate layer, which was assumed to be related with the structure of polyols. Especially polyol polyacrylates with the skeleton of pentaerythritol were superior in surface-curability to those with the skeleton of trimethylolpropane. On the other hand, there was almost no difference in surface-curability for EB-curing among the polyol polyacrylates. About 0.4 Mrad dosage caused the surface of the polyol polyacrylate layer to harden. By ESR apectoscopic analysis, it was confirmed that the accumulation of stable radicals and the formation of polymer networks progressed simultaneously.View full abstractDownload PDF (1112K) -
Toshio OKADA, Tsutomu ASANO, Motoyoshi HATADA, Jun-ichi TAKEZAKI, Koic ...1987 Volume 44 Issue 10 Pages 761-770
Published: October 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe effects of initiator type, concentration of initiator and molecular weight of oligomer were studied in the EB curing of bisphenol A diglycidyl ether type epoxy oligomer containing an onium initiator. Cured products of above 95% of gel contents were obtained from liquid oligomers with an onium initiator content of 0.05 mol/kg. For solid oligomers the final levelling-off gel content decreased with increasing molecular weight of the original oligomer. However, unreacted epoxide bonds still remained in the cured system, although the gel content had almost reached its maximum. The post effect of curing was observed the present system. After irradiation, the decay of epoxide bonds continues following first order reaction kinetics and the apparent rate constant is directly proportional to the preirradiation dose. Dynamic mechanical studies show that heat-treatment after room temperature irradiation gives the cured product of higher glass transition temperature and crosslinking density than those of the product cured with tertiary amine at elevated temperature.View full abstractDownload PDF (1469K) -
Maki ITOH, Toshiaki SHIOTA, Minoru NISHIHARA1987 Volume 44 Issue 10 Pages 771-777
Published: October 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe effect of chemical structure of acrylate monomers on their electron beam polymerization behavior has been studied. Structural analysis showed that commercial triacrylates were mixtures of di-, tri-, and tetra-acrylates. Therefore, average numbers of acryloyl groups per molecule deviated from three. However, a monomer containing a greater number of unsaturated groups did not always yield a polymer of higher hardness. Harder polymer was obtained from a hydroxyl-containing triacrylate monomer at a low extent of reaction of carbon-carbon double bonds. The rate of polymerization of a monoacrylate monomer containing a hydroxyl was several times higher than that without hydroxyls. The polymerization proceeded by a radical mechanism. Acceleration of polymerization can be explained by an increase in the number of initiating species by the formation of radicals from the hydroxyl, and by the autoacceleration effect arising from both higher viscosity of the monomer and an increase in viscosity of the reaction system by cross-linking.View full abstractDownload PDF (1365K) -
Koji MORI, Kenji KOSHIISHI, Ken-ichi MASUHARA1987 Volume 44 Issue 10 Pages 779-786
Published: October 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSMixtures of acrylates were cured by electron beams. Surface tensions of those acrylic base films were controlled by changing the mixing ratio of acrylates. The grafting was carried out by coating methyl methacrylate on the base film and irradiating with electron beams. The contribution ratios γp G/γd G of the surface tension of grafted base films decrease as the contribution ratios γpB/γd B of the surface tension of base films increase. It is assumed that the grafting side chains (poly (methyl methacrylate)) exist on the base film as nearly mono-molecular layers, and that those conformations were arranged by the interaction between the base film and the grafting side chain. The surface tensions of methyl methacrylate bulk polymers and poly (methyl methacrylate) casting films can be contrasted with the base films which had various surface tensions. The conclusion is that the covering ratio of the grafting side chains on the base films was controlled to minimize interfacial tensions against the base films during the graft-polymerization.View full abstractDownload PDF (1365K) -
Masayuki ANDO, Toshiyuki URYU1987 Volume 44 Issue 10 Pages 787-792
Published: October 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe gel films obtained by electron beam (EB) solid-state polymerization of urethane-acrylate prepolymers were characterized by differential scanning calorimetry (DSC). Two kinds of urethane-acrylates were synthesized by reaction of poly (butylene adipate) diol (PBAD), 4, 4′-diphenylmethane diisocyanate (MDI) and 2-hydroxyethyl acrylate (HEA) for this purpose. One is a semicrystalline prepolymer (UA-251M) with a number average molecular weight (Mn) of 3200, and the other is an amorphous one (UA-071M) with Mn of 1450. The Mn varied by changing Mn of PBAD. UA-251M gel film decreased in glass transition temperature (Tg) and increased in heat capacity change (ΔCp) at Tg with increasing irradiation dose, while the Tg and ΔCp, values of UA-071M gel film changed in the opposite way to those of UA-251M gel film. Above 5 Mrad, gel fraction reached more than 90%, and the Tg and ΔCp values changed steeply for both prepolymers. This steep change in Tg and ΔCp was attributed to the crosslinking of PBAD chains as well as of terminal acryloyl groups. Since the Tg change of UA-071M gel film depends merely on the crosslinking, the crosslinking structure was evaluated using two equations which relate the shift in Tg to crosslinking. The molecular weight between crosslinking junctions was found to be larger than the Mn, of the prepolymer. The crosslinking by the EB polymerization restricted the mobility of the polymer chain less strongly than the crosslinking by the three-functional isocyanate and α, ω-dihydroxy (polypropylene oxide) with a molecular weight of 1000 did.View full abstractDownload PDF (917K) -
Minoru SASHIO, Ken-ichiro YANO, Masahiro TSUNOOKA, Makoto TANAKA1987 Volume 44 Issue 10 Pages 793-796
Published: October 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPhotocrosslinking of vinyl acetate-isopropenyl acetate (VAc-IPAc) copolymer was studied in the solid state in the presence of various quinones. The photocrosslinking reaction in the presence of p-benzoquinone and naphthoquinone proceeded very easily with irradiation. Photocrosslinking efficiency of partially hydrolyzed copolymer films was lower than that of VAc-IPAc copolymer films. Especially, the photocrosslinking efficiency of copolymer films partially hydrolyzed at random was lower than that of copolymer films partially hydrolyzed in a block way. The acetoxy groups in the copolymers were deduced to play an important role in the photocrosslinking because the crosslinked polymers could be made water soluble on hydrolysis.View full abstractDownload PDF (494K)
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